Dental impression tray



E. R. SMITH.

DENTAL IMPRESSION TRAY.

APPLICATION FILED NOV- s, 1921.

1,422,488, Patented July 11,1922.

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WITNESS INVENTOR Y g I: i a v Elm/5 T /7/77? 0 ATTORNEYS metre sta ns ERNEST ROBERT SMITH, OF SAN FRANCISCO, CALIFORNIA.

IDENTAL IMPRESSION TRAY.

intense.

Specification of Letters Patent.

Patented July it, 1922.

Application filed November 3, 1921. Serial No. 512,578.

T 0 all whom it may concern:

Be it known that I, ERNEST ROBERTSMITI-I,

a citizen of the United States, and a resident of the city and county of'San Francisco, State'of California, have invented a new and useful Dental Impression Tray, of which the following is a specification.

This invention relates to dentistry and particularly to tin-apparatus for making impressions of the tooth system of the oral cavity. 7 I

The use of small trays filled with a plastic material which is applied to a tooth or teeth in given cases so as to get an accurate impression for the making of plates, partial plates, fixed and removable bridges, crown and acket crown construction and in orthodontia is well known and it has been heretofore proposed to utilize a divided tray to assist in the removal of the hardened plaster incases where there-may be under-cut tooth structure and malformations or fractures which prevent the direct axial withdrawal of the cast with respect to the tooth or teeth.

An object of the present invention is to provide for the effective'manipulation, application, securing and removal of a split dental tray and therefore to eliminate the injury to the impression during the removal of the tray and preserve the fine lines and enable the apposition of the halves after the cast has'been removedfrom the oral cavity.

Another object is to enable the dentist to obtain a perfect model and to provide for convenience to the dentist and for comfort to the patient, to economize in time in the making of the impressions and the assembling of the halves after the removal of the split tray and in separating after the impression has been pourech An object is to provide a device which is of extremely simple, inexpensive and practical construction and which combines a handle portion for facilitating the manipulation of the device and which also serves as means for setting and removing a fastening element.

The invention possesses other objects and features of advantage, some of "which, with the foregoing, will be made manifest in the following description of the preferred form of the invention, which is illustrated in the drawings accompanying and forming partof the specification. It is to be understood that it is not intended to limit the invention to the embodiment shown by the said drawings and description, as variations may be adopted within the scope of the invention as set forth in the claims.

.Fig. 1 is a perspective of the improved device, as ready for use.

. Fig. 2 is a plan of the tray .detached from the handle.

Fig. 3 is a cross section on a plane indicated by line 3-43 of Fig. 2 to show the registering means; the section being considerably enlarged. i

Fig. 4% is a cross sectional view transversely of the tray and showing thefastening means.

Fig. 5 is a section across the axis of the nut, showing the wrench slots.

Fig. 6 is a plan of the handle-wrench, broken away.

Fig. '7 is a cross section on the plane indicated at line 7-7 of Fig. 6. i

The device of the present invention may be embodied in a tray-like structure some what resembling a boxopen at oneend, and atone sidewhlch may be termed the top, and being divisible into similar sections along the parting line. As shown, the tray consists of sections 2 and 3 of a substantially right and left hand character, each being provided with a base orbottom portion 4c having perpendicular side flanges 5 and transverse perpendicular end walls 6 which have concaved top edges 7. The sections .23 are provided with meeting lips 8 and 9 extending medially ofthe assembled tray and preferably having somewhat sharpened upper edges 10. The end of the tray that is opposite to the walls 6 is open and the parts are preferably registered when assembled at the parting plane by suitable means, such as a lug 11 and a seat 12 in opposed faces of the lips 8 and 9.

An important feature of the present in vention consists of means for effectively holding the sections assembled, and in the present case such means consists of a split post formed 'by complementary meeting parts 13 which extend perpendicularly from the outer surface of the bottom or base at of the tray; the parts 18 meeting on the diametrical parting plane of the sections. Clhe lower end of the split post is preferably threaded, as at 14:. Upon the post is adapted to be readily applied and screwed up a fastening element, such as nut 15.

To facilitate and save time in the application of the nut to the split post, one face of the nut is shown as provided with a conical counter-bore 16, and this is disposed toward the post in the act of applying the nut. It will be seen that by this construction and arrangement the tray parts are made of inexpensive construction and may be quickly assembled and fastened together to receive a plaster material and when the loaded tray is applied in the oral cavity, the parts being of compact arrangement will lie comtortably in the cavity, since the fastening means consisting of the screw and nut are in a position closely contiguous to the outer face of the base 4 of the tray.

To further facilitate the use of the device a handle part is provided and may consist of a small strip or bar 17, one end of which is apertured, as at 18, to form lateral tongues adapted to readily pass into diametrically opposite slots or seats 19 provided in the sides of the nut 15, The handle therefore, forms not only a means for facilitating the application of the tray and the handling of the same when removed from the mouth, but also provides means applicable to the nut to turn or set the same up tight on the screw post 13, after which the handle can be instantly removed if desired, while the tray is left for a period suficient to permit the setting of the plaster to the tooth system in the mouth. The handle 17 may then be re-applied and the nut loosened up sufliciently to enable its removal by the fingers, after which the sections 2 and 8 are separated in such cases as maybe neces' sary owing to the tooth structure. During the separation of the traysections the hardened plaster is broken longitudinally, substantially on the meeting plane between the lips 8 and 9 which, as above stated, are pro vided with sharpened meeting edges which tends to direct the line of fracture through the hard-ened plaster.

For convenience the removable handle 17 may have a portion of its edge sharpened, as at 17 for application to the seam formed at the meeting faces of the tray sections so that pressure of the splitting tool, formed by the handle, divides the set plaster, as above suggested, after the nut 15 has been removed and therefore enabling the lateral separation of the tray sections from the tooth or teeth and avoids distorting the impression. After the sections have been removed from their respective sides of the tooth structure, they are again re-assembled and the fine lines of fracture will be preserved and will closely meet when the halves are replaced in apposition. The nut 15 is applied to the re-assembled sections to hold the same together.

The nut 15, not only holds the sections 2--3 together, but forms a setting up and ,asa

re-enforcing means wheiijammed up against the bottoms of the sections.

It is understood that, while a tray of a form open at one end is here shown, it is within the scope of this invention to make trays open at either end or closed on four sides, according to the work in hand.

What is claimed is:

1. A dental device consisting of a divided, impression-taking tray, a split post perpendicular to and on the bottom of the tray and means for clampingthe tray sections together and being detachably carried by the tray while it is applied, and consisting of nut mounted on said: post and jamming against the tray bottom, g

2. A dental device consisting of an impression-taking tray having apposable sec tions each having a projecting part on its base, and a nut engageable with the said parts ,to hold the sections together.

3. A dental device consisting of an impression-taking tray having apposable sections each having a projecting part on its base, and a fastener engageable with the said. parts to hold the sectionstogether; said parts each consisting of 'a half-screw, and said fastener consisting of anut.

4. A dental impression-taking tray consisting of apposable sections, and split screw on the base of the tray and a nut applicable to said split screw for securingthe sections tog-ether.

5. A dental impression-taking tray consisting of apposable sections, and a screw and a nut therefor on the base of the tray for securing the sections together, one half of the screw being carried by each section.

6. A dental impression-taking tray' consisting of apposable sections, screw and nut means on the base of the tray for-securing the sections together, and a handle member adapted to be applied to set the nut and for "facilitating the manipulation of the tray.

7. A dental impression-taking tray consisting of apposable sections, a, screw and grooved nut on the base of the tray for securing the sections together, and ahandle member having a torkedend adapted to be applied to the grooves of the nut and for facilitating the manipulation of the tray and for setting and loosening the nut, and being frictionally retained onthe nut.

8. A dental device consisting of a tray having apposable sections with plane meeting faces one of which has a pocket for registering with a lug on the other member of the sections.

In testimony whereof, I have hereunto set my hand. i I

ERNEST ROBERT SMITH. 

